The present invention relates to a cylinder phase adjustment controlling apparatus for various types of printing presses, which performs control to automatically adjust the phase of a cylinder, e.g., a plate cylinder, in the circumferential direction when the specifications of a printed matter are changed or a plate is to be mounted on the cylinder.
A sheet printing press with a reversing mechanism that can be convertibly used both for one-side printing and two-side printing is known as one type of a printing press. FIG. 3 shows the cylinder arrangement of a sheet printing press with a reversing mechanism of this type for explaining an one-side printing operation, and FIG. 4 shows the cylinder arrangement of the same for explaining a two-side printing operation. Referring to FIGS. 3 and 4, a blanket cylinder 2 is provided under and in contact with an upstream plate cylinder 1 on which a plate is mounted. Similarly, a blanket cylinder 4 is provided under and in contact with a downstream plate cylinder 3 on which a plate is mounted. Reference numeral 5 denotes a double-diameter cylinder having a diameter twice that of the cylinder 1 or 3. An impression cylinder 6 and a transfer cylinder 7 are disposed in contact with each other between the double-diameter cylinder 5 and the upstream blanket cylinder 2, and a reversing cylinder 8 and an impression cylinder 9 are disposed in contact with each other between the double-diameter cylinder 5 and the downstream blanket cylinder 4. Reference numeral 10 denotes a paper feed cylinder which is in contact with the upstream impression cylinder 6.
Of these cylinders, the paper feed, impression, transfer, reversing, impression, and double-diameter cylinders 10, 6, 7, 8, 9, and 5 have gripper units (to be referred to as grippers hereinafter) 11, 12, 13, 14, 15, 16, and 17 each made of an openable/closable gripper member and a gripper table. The grippers 11, 12, 13, 14, and 15 are disposed in the outer circumferential gaps of the paper feed, impression, transfer, reversing, and impression cylinders 10, 6, 7, 8, and 9. The grippers 16 and 17 are disposed in the gaps formed at positions of the double-diameter cylinder 5 to equally divide the outer circumferential portion thereof into two portions in the circumferential direction. Reversing grippers 18 having an arrangement the same as those of the above grippers are disposed in the outer circumferential gap of the reversing cylinder 8 to be close to the grippers 14. Chuck heads 19 and 20 are provided at portions of the double-diameter cylinder 5 that equally divide the outer circumferential portion of the double-diameter cylinder into two portions. The chuck heads 19 and 20 are ahead of the grippers 16 and 17, respectively, by predetermined angles in the rotating direction of the cylinder 5 indicated by an arrow in FIG. 4. The respective cylinders are coupled to each other and driven by cylinder gears provided at their shaft end portions, as will be described later. Reference numeral 21 denotes a feed board inclinedly supported between a paper feed unit (not shown) and the paper feed cylinder 10; and 22, paper fed onto the feed board 21.
With this arrangement, in the case of one-side printing shown in FIG. 3, when the respective cylinders are rotated in the directions indicated by arrows, the paper 22 fed from the paper feed unit onto the feed board 21 is gripped by the grippers 11 of the paper feed cylinder 10, conveyed by a predetermined angle by the rotation of the paper feed cylinder 10, transferred to the gripper 12 of the impression cylinder 6, and wound on the circumferential surface of the impression cylinder 6. Since an image formed on the plate surface of the plate cylinder 1 is transferred to the blanket cylinder 2, this image is transferred to the paper 22 passing between the blanket and impression cylinders 2 and 6, thereby performing printing of the first color.
The printed paper 22 is transferred from the grippers 12 of the impression cylinder 6 to the grippers 13 of the transfer cylinder 7, then to the grippers 16 or 17 of the double-diameter cylinder 5, and wound on the upper circumferential surface of the double-diameter cylinder 5. As the double-diameter and reversing cylinders 5 and 8 are rotated, the wound paper 22 is transferred from the grippers 16 or 17 to the opposite grippers 14, and to the grippers 15 of the impression cylinder 9. At this time, since the image formed on the plate surface of the plate cylinder 3 is transferred to the blanket cylinder 4, this image is transferred to the paper 22 passing between the blanket and impression cylinders 4 and 9, thereby performing printing of the second color. In this case, since the image from the upstream blanket cylinder 2 and the image from the downstream blanket cylinder 4 are transferred on the same surface of the paper 22, one-side printing is performed. The paper 22 subjected to one-side printing is conveyed to a following printing unit or paper discharge unit (not shown).
The operation of two-side printing will be described with reference to FIG. 4. When one-side printing is switched to two-side printing, the whole upstream cylinder group including the double-diameter cylinder 5 is phase-adjusted by a phase adjusting unit (to be described later) with respect to the reversing cylinder 8, so that a state of FIG. 3 wherein the grippers 17 and 14 oppose each other is changed to a state of FIG. 4 wherein the reversing grippers 18 oppose the chuck head 19 or 20. Also, the operation timings of the cam mechanisms for opening/closing the grippers 16 and 17 are adjusted. When the respective cylinders are rotated to start the printing operation, the paper 22 having a printed surface is transferred to the grippers 16 or 17 of the double-diameter cylinder 5, in the same manner as in the case of one-side printing, and wound on the upper circumferential surface of the double-diameter cylinder 5.
In this case, after the grippers 16 or 17 pass over the contact points of the double-diameter and reversing cylinders 5 and 8, the two cylinders 5 and 8 continue rotation. Then, the paper 22 wound on the upper circumferential surface of the double-diameter cylinder 5 is wound on the lower circumferential surface of the double-diameter cylinder 5, as indicated by a reference symbol 22A in FIG. 4. While the paper trailing end of the paper 22A is located at the contact point of the double-diameter and reversing cylinders 5 and 8, the reversing gripper 18 of the reversing cylinder 8 is opened and closed. Thus, the paper trailing end of the paper 22A is gripped by the reversing grippers 18 by the cooperation of the reversing grippers 18 and the opposite chuck head 19 or 20. As a result, the lower surface of the paper 22A is brought into contact with the circumferential surface of the reversing cylinder 8, and the upper surface of the paper 22A is brought into contact with the circumferential surface of the impression cylinder 9. Printing is performed on the lower surface of the paper 22A passing between the blanket and impression cylinders 4 and 9. Since printing has been performed on the upper surface of the paper 22 by the blanket cylinder 2, two-side printing is eventually performed.
The conventional phase adjusting unit for adjusting the phases of the upstream cylinder group including the double-diameter cylinder 5 when one-side printing is switched to two-side printing, as described above, will be described. Referring to FIG. 3, the respective cylinders are coupled and driven by cylinder gears provided to their shaft end portions. Of these cylinder gears, the cylinder gear of the reversing cylinder 8 is constituted by stationary and pivot gears that are coupled to each other to be freely fixed or released with or from each other. The stationary gear of the cylinder gear of the reversing cylinder 8 is fixed to the end shaft of the reversing cylinder 8 and meshed with the cylinder gear of the impression cylinder 9, and the rotational gear thereof is meshed with the cylinder gear of the double-diameter cylinder 5.
With this arrangement, when one-side printing is to be switched to two-side printing, the stationary and pivot gears are released from each other, and the pivot gear is pivoted by, e.g., a handle. Then, the cylinders 5, 7, 6, 2, 1, and 10 of the upstream printing cylinder group including the double-diameter cylinder 5 are simultaneously pivoted by meshing of their cylinder gears, and their phases in the circumferential directions with respect to the reversing cylinder 8 are adjusted. Then, the stationary and pivot gears of the cylinder gear of the reversing cylinder 8 are fixed, thereby completing phase adjustment.
In the case of two-side printing, the position of a pattern printed on the upper surface of the paper 22 and the position of a pattern printed on the lower surface of the paper 22 are misregistered from each other depending on the printing or mounting position of the plate. Furthermore, in two-side printing, printing is sometimes performed by intentionally misregistering the pattern position of the upper surface and the pattern position of the lower surface of the paper 22. For this purpose, as shown in FIG. 3, a cylinder gear 23 of the plate cylinder 1 is fitted on an end shaft 1a thereof by a bolt or the like to be freely fixed or released with or from it, and the cylinder gear 23 is meshed with a cylinder gear 25 of the impression cylinder 6 through a cylinder gear 24 of the blanket cylinder 2. The cylinder gear 25 of the impression cylinder 6 is meshed with a gear 26, and a gear 27 integrally fixed with the gear 26 is meshed with a gear 29 fixed to a rotary encoder 28 for outputting a rotation pulse to a controller (not shown).
With this arrangement, when the bolt for fixing the cylinder gear 23 of the plate cylinder 1 is loosened to pivot and adjust the plate cylinder 1 and this fixing bolt is fixed, vertical registration of the plate is adjusted. Also, for example, when the plate cylinder 1 is to be stopped at a predetermined position for plate exchange or the like, the plate cylinder 1 is driven by a motor, so that the stop position of the plate cylinder 1 is controlled with reference to an output from the rotary encoder 28 connected to the controller.
In the conventional cylinder phase adjustment controlling apparatus, however, the phases of the cylinders are adjusted with reference to the output from the rotary encoder 28, as described above. Therefore, when phase adjustment is performed by changing the phases of, e.g., the plate cylinder 1 and the cylinder gear 23, the phase of the plate cylinder 1 cannot be detected from the output from the rotary encoder 28, and the stop position of the plate cylinder 1 is shifted from the preset position by a moving adjustment amount. Then, the phase adjustment of the plate cylinder 1 cannot be controlled at a timing of the printing press side, so that the phase adjustment precision is degraded, and the preparation time is prolonged by readjustment, resulting in degradation in operability of the machine. These problems arise not only in the sheet printing press with the reversing mechanism described above, but also in a conventional one-side multi-color printing press, since the phases of the plate cylinder and cylinder gears are shifted from each other for registration of different colors.